The invention relates to a piston-type lock of the type comprising a cylindrical rotor pivoting in a longitudinal bore of a stator, the said rotor comprising a longitudinal key passage and a plurality of radial bores opening into the key passage and to the periphery of the rotor, the said stator comprising a plurality of bores opening into the longitudinal bore of the stator and, in one angular position of the rotor, each prolonging a radial bore of the rotor, each radial bore of the rotor containing a sliding piston and each radial bore of the stator containing a sliding piston spring-loaded towards the longitudinal bore of the stator, the pistons of the rotor each co-operating with a piston of the stator in the said angular position, the inner extremities of the pistons of the rotor co-operating with the notches of a coded key introduced into the key passage in such manner that the other extremities of the said pistons of the rotor are flush with the periphery of the rotor.
While locks of this type offer great security by reason of the multiplication of the number of combinations and their resistance to force, their fitting is very delicate and difficult to automate.
In order to facilitate the fitting of these locks it has been proposed to lodge the stator pistons with their springs in a separate support which is then fixed to the stator, the pistons being liberated after fitting of the rotor. This proposal improves the fitting of the locks but renders the assembling of the lock still more difficult. Moreover it necessitates mutually identical pistons for the stator.